Tourette Syndrome, Chronic Tic Disorder Up the Risk of Cardiometabolic Disease

People who have Tourette syndrome or chronic tic disorder are at a much greater risk of also having metabolic and cardiovascular diseases, according to an analysis of Swedish epidemiologic data spanning four decades.

“Until recently, we knew very little about the physical health of individuals with Tourette syndrome and chronic tic disorders, particularly in the long run. The Swedish registers, which have full coverage of the population’s medical health records for over 40 years, offered a unique opportunity to examine the long-term health status of these patients,” senior author Lorena Fernández de la Cruz, PhD (Karolinska Institutet, Stockholm, Sweden), told TCTMD in an email, adding, “These results are entirely novel, and we hope they will be helpful to clinicians working with this patient group.”

The current findings, which come from an observational study and require replication, probably do not indicate patients with tic disorders require a referral to a cardiologist, she said. “However, careful monitoring of risk factors by the treating physician (eg, child psychiatrist, neurologist, or even [general practitioner]) is warranted,” given that metabolic and cardiovascular disorders can result in premature mortality.

“Our clinical impression is that the awareness about the link between tics and cardiometabolic risks is low among sufferers. An increased knowledge of it may motivate behavioral changes in this group of patients, such as [more] physical activity and the promotion of healthier lifestyles,” Fernández de la Cruz suggested.

Lead author Gustaf Brander, MSc (Karolinska Institutet), and colleagues described their findings in a paper published online earlier this week in JAMA Neurology.

Differences Emerge at Age 8

The investigators sought to better understand any risks of metabolic and cardiovascular disorders related to Tourette syndrome or chronic tic disorder, both of which fall under the category of tic disorders. They conducted a longitudinal, population-based cohort study looking at all people living in Sweden between 1973 and 2013, in particular identifying families containing a mixed group of nontwin siblings with and without the two disorders.

Of the more than 14 million people in the cohort, around 7,800—half a percent—had been diagnosed by a specialist as having Tourette syndrome or chronic tic disorder. Three-quarters of these individuals were men, with a median age at diagnosis of 13.3 years.

Of the 2.6 million families with at least two full siblings, 5,141 (0.19%) had children who had and had not been diagnosed.

The cumulative incidence of any cardiometabolic disorder was estimated at 52.5% and 29.5% for people with versus without a diagnosis. Notably, Kaplan-Meier curves for this endpoint began to separate when individuals were 8 years old.

Compared with the general population, people with Tourette syndrome or chronic tic disorder were at higher risk of having a cardiometabolic disorder (adjusted HR 1.99; 95CI 1.90-2.09). And though the difference was not as great, their risk was also higher than that of sibling controls (adjusted HR 1.37; 95% CI 1.24-1.51).

Individuals With Tourette Syndrome or Chronic Tic Disorder vs General Population

Among those with a Tourette/chronic tic disorder diagnosis, the increase in cardiometabolic risk versus the general population was more acute for men (adjusted HR 2.13; 95% CI 2.01-2.26) than for women (adjusted HR 1.79; 95% CI 1.64-1.96), as was the risk of obesity.

Most comorbidities didn’t affect the association, with the exception of attention-deficit/hyperactivity disorder—excluding these patients muted the increase in risk of developing a cardiometabolic disorder.

“The results highlight the importance of carefully monitoring cardiometabolic health in patients with Tourette syndrome or chronic tic disorder across the life span, particularly in those with comorbid attention-deficit/hyperactivity disorder,” Brander and colleagues conclude.

Additionally, patients with Tourette syndrome or chronic tic disorder were at lower risk if they had been taking antipsychotic treatment for more than 1 year, though Brander et al caution that this link may be due to confounding rather than the medication itself—in that patients able to maintain drug therapy are inherently a different group than those who can’t and are likely receiving better healthcare as a whole.

That there was still a 37% increase in risk for people with a tic disorder even when comparing siblings suggests at least some of the association can be attributed to the disorders in and of themselves, the investigators point out.

People affected by these conditions “experience a substantial number of stressors in their daily lives, have poorer educational outcomes, and, like individuals with other neuropsychiatric disorders, might have unhealthier lifestyles (eg, lack of physical activity and poor diet), which have also been shown to be associated with the development of metabolic and cardiovascular disease,” the researchers explain.

To TCTMD, Fernández de la Cruz said the next step is to study whether these risks translate into premature mortality and to seek whether there are any shared familial risk factors at play.